Telescopic handle for luggage cart

ABSTRACT

A telescopic handle for luggage cart includes a simplified locating mechanism for conveniently locking tubes of the telescopic handle in place when the tubes have been pulled to a fully extended position. The tubes of the telescopic handle could be extended and telescoped relative to one another without the need of a pushbutton mechanism. Instead, the telescopic handle employs elastically retractable steel balls to enable automatic locking of the extended tubes of the telescopic handle in place, so that the handle could be more conveniently operated.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a telescopic handle for luggage cart, and more particularly to a telescopic handle for luggage cart in which telescopic tubes of the handle could be easily extended and locked in place to enable convenient operation of the handle.

[0002] People use portable bags or other containers, such as trunks, cases, etc., to pack and carry necessary items, particularly when people go to other distant places for traveling, working, visiting friends, studying, etc. Most currently available trunks or traveling bags include wheels or casters and a telescopic handle. When the telescopic handle is in an extended state, a user may conveniently pull or push the trunk or traveling bag at the handle to move around easily in an effortless manner.

[0003] The above-mentioned conventional telescopic handle includes diametrically smaller inner tubes slidably received in diametrically larger outer tubes, so that the inner tubes could be extended or retracted relative to the outer tubes. Both the inner tubes and the outer tubes include laterally symmetrical left and right tubes. A horizontal handle grip is connected to upper ends of two innermost tubes. A user may pull or push the handle at the handle grip to effortlessly move the trunk or traveling bag connected to the telescopic handle. A push button is provided on the handle grip to control an elastic button projected into the tubes, so as to decide the amount by which the tubes are to be extended. That is, when the user intends to extend or retract the telescopic handle, the push button on the handle grip must be depressed and held before the tubes of the handle could be extended or retracted. In the event the push button is damaged, it would be very difficult or impossible to extend or retract the telescopic tubes of the handle.

[0004] It is therefore tried by the inventor to develop a telescopic handle for luggage cart, the telescopic tubes of which could be extended or retracted without any push button, making the telescopic handle simpler and more convenient for use.

SUMMARY OF THE INVENTION

[0005] The telescopic handle for luggage cart according to the present invention mainly includes a lower frame for connected to a trunk or a luggage seat of a luggage cart, an upper frame, and middle tubes slidably connected at two ends to the lower and the upper frames. The lower frame includes left and right square lower tubes, each of which has a hollow stop plug connected to an upper end thereof. The upper frame includes a left and a right square upper tube and a horizontal handle grip connected to upper ends of the left and the right upper tubes. Each of the upper tubes has a locating piece connected to a lower end thereof, and the locating piece is provided with an elastically retractable steel ball. Each of the middle tubes is provided at an upper end with a hollow stop plug and at a lower end with a locating piece having an elastically retractable steel ball. The lower tubes of the lower frame are provided near the upper ends with locating holes adapted to engage with the steel balls on the locating pieces at the lower ends of the middle tubes, so as to automatically lock the middle tubes in an extended position relative to the lower frame. Similarly, the middle tubes are provided near the upper ends with locating holes adapted to engage with the steel balls on the locating pieces at the lower ends of the upper tubes of the upper frame, so as to automatically lock the upper frame in an extended position relative to the middle tubes.

[0006] In the telescopic handle for luggage cart of the present invention, each of the stop plugs has an inner diameter smaller than an outer diameter of the locating piece corresponding to the stop plug, preventing the locating piece from moving out of the tube to which the locating piece is connected.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

[0008]FIG. 1 is an exploded perspective view of a three-section telescopic handle for luggage cart according to the present invention;

[0009]FIG. 2 is an assembled perspective view of the telescopic handle of FIG. 1 in a fully extended state;

[0010]FIG. 3 is a fragmentary sectioned side view of the telescopic handle of FIG. 1 in an extended state;

[0011]FIG. 4 is a fragmentary sectioned side view of the telescopic handle of FIG. 1 in a partially telescoped state;

[0012]FIG. 5 is an assembled perspective view of the telescopic handle for luggage cart of FIG. 1 in a fully telescoped state; and

[0013]FIG. 6 is a perspective view of a two-section telescopic handle for luggage cart according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Please refer to FIGS. 1 and 2 that are exploded and assembled perspective views, respectively, of a three-section telescopic handle for luggage cart according to the present invention. As shown, the three-section telescopic handle, which is generally denoted by reference number 20, includes a lower frame 21 for firmly connected to a trunk or a luggage seat 10 of a luggage cart, an upper frame 22 providing a handle grip 25, and two laterally symmetrical middle tubes 23 interconnecting the lower and the upper frames 21, 22.

[0015] The lower frame 21 includes left and right lower tubes 24. In the illustrated embodiment, the lower tubes 24 have a square cross section. Each lower tube 24 has a hollow stop plug 211 defining a central hole 212 connected to an upper end of the lower tube 24. The two middle tubes 23 are separately extended through the central holes 212 of the stop plugs 211 to locate in the left and the right lower tubes 24.

[0016] The upper frame 22 includes a handle grip 25 connected to upper ends of a left and a right upper tube 26 that are also square tubes. Each upper tube 26 has a locating piece 221 fixedly connected to a lower end of the upper tube 26. The locating piece 221 is provided with a radial hole 222 for accommodating a tension spring 223 and a steel ball 224 therein.

[0017] Each middle tube 23 has a hollow stop plug 231 defining a central hole 232 connected to an upper end of the middle tube 23, and a locating piece 233 connected to a lower end of the middle tube 23. The upper tubes 26 are separately extended through the central holes 232 of the stop plugs 231 to locate in the left and the right middle tubes 23. Each locating piece 233 is provided with a radial hole 234 for accommodating a tension spring 235 and a steel ball 236 therein.

[0018] The lower tubes 24 of the lower frame 21 are provided near their upper ends with locating holes 241 adapted to engage with the steel balls 236 received in the locating pieces 233 at the lower ends of the middle tubes 23 and normally pushed outward by the tension springs 235. The engagement of the locating holes 241 with the steel balls 236 automatically locks the middle tubes 23 in place when the middle tubes 23 have been pulled to a fully extended position relative to the lower frame 21.

[0019] The middle tubes 23 are provided near their upper ends with locating holes 237 adapted to engage with the steel balls 224 received in the locating pieces 221 at the lower ends of the upper tubes 26 and normally pushed outward by the tension springs 223. The engagement of the locating holes 237 with the steel balls 224 automatically locks the upper frame 22 in place when the upper frame 22 has been pulled to a fully extended position relative to the middle tubes 23.

[0020] Please refer to FIGS. 3 and 4. The hollow stop plug 211 at the upper end of each lower tube 24 of the lower frame 21 has an inner diameter smaller than an outer diameter of the locating piece 233 at the lower end of each middle tube 23, so as to prevent the locating piece 233 and accordingly the middle tube 23 from moving out of the lower tube 24. When the middle tubes 23 are fully extended from the lower tubes 24, the steel balls 236 in the locating pieces 233 connected to the lower ends of the middle tubes 23 are pushed by the tension springs 235 to partially engage into the locating holes 241 near the upper ends of the lower tubes 24 and thereby lock the extended middle tubes 23 in place without moving any further, as shown in FIG. 3. As shown, the locating pieces 233 at the lower ends of the middle tubes 23 have an outer diameter similar to an inner diameter of the square lower tubes 24, and the middle tubes 23 have an outer diameter similar to an inner diameter of the central holes 212 of the hollow stop plugs 211 at the upper ends of the lower tubes 24, so that the middle tubes 23 are allowed to smoothly slide in the square lower tubes 24 of the lower frame 21 without becoming loosely swung relative to the lower frame 21.

[0021] The hollow stop plugs 231 at the upper ends of the middle tubes 23 have an inner diameter smaller than an outer diameter of the locating pieces 221 at the lower ends of the upper tubes 26 of the upper frame 22, so as to prevent the locating pieces 221 and accordingly the upper tubes 26 from moving out of the middle tubes 23. When the upper tubes 26 of the upper frame 22 are fully extended from the middle tubes 23, the steel balls 224 in the locating pieces 221 connected to the lower ends of the upper tubes 26 are pushed by the tension springs 223 to partially engage into the locating holes 237 near the upper ends of the middle tubes 23 and thereby lock the extended upper tubes 26 in place without moving any further, as shown in FIG. 3. As shown, the locating pieces 221 at the lower ends of the upper tubes 26 have an outer diameter similar to an inner diameter of the middle tubes 23, and the upper tubes 26 have an outer diameter similar to an inner diameter of the central holes 232 of the hollow stop plugs 231 at the upper ends of the middle tubes 23, so that the upper tubes 26 are allowed to smoothly slide in the middle tubes 23 without becoming loosely swung relative to the middle tubes 23.

[0022] To fully extend the telescopic handle 20, simply hold the handle at the handle grip 25 and apply a pulling force larger than a tension provided by the tension springs 223, 235 and the upper frame 22 and the middle tubes 23 could be sequentially pulled out of the lower frame 21, as shown in FIG. 3. No other operating button is needed to extend the telescopic handle 20, allowing the handle 20 to be operated in an even more conveniently manner. The omission of the push button that usually includes complicate structure also allows the telescopic handle 20 to be manufactured at reduced cost.

[0023] To collapse the telescopic handle 20, simply apply at the handle grip 25 of the upper frame 22 a force larger than the tension provided by the tension springs 223, and the steel balls 224 could be pushed backward into the radial holes 222 and disengaged from the locating holes 237 to allow the upper tubes 26 of the upper frame 22 to retract into the middle tubes 23, as shown in FIG. 4. Similarly, apply the force further could push the middle tubes 23 into the square lower tubes 24 of the lower frame 21. When the upper tubes 26 are fully telescoped in the middle tubes 23 and the middle tubes 23 in the lower tubes 24, as shown in FIG. 5, the tubes 26, 23 are respectively tightly fitted in the stop plugs 231, 211 without the risk of easily sliding out of the telescoped position.

[0024] The middle tubes 23 are laterally symmetrically provided on the telescopic handle 20. Normally, one left and one right middle tube 23 shall be sufficient to provide a three-section telescopic handle 20. In another embodiment of the present invention, the middle tubes 23 are omitted and the upper tubes 26 of the upper frame 22 are directly telescopically received in the square lower tubes 24 of the lower frame 21 to provide a two-section telescopic handle 20′, as shown in FIG. 6.

[0025] The telescopic handle for luggage cart according to the present invention employs the simple principle of elastically retractable steel balls to enable automatic locking of the tubes of the telescopic handle in place, so that the handle could be more conveniently operated and manufactured at reduced cost. 

What is claimed is:
 1. A telescopic handle for luggage cart, comprising a lower frame for firmly connected to a trunk or a luggage seat of a luggage cart, an upper frame, and two laterally symmetrical middle tubes slidably extended between said lower frame and said upper frame; said lower frame including left and right square lower tubes, said upper frame including left and right square upper tubes and a handle grip connected to upper ends of said left and said right upper tubes; said telescopic handle being characterized in that: each of said left and said right lower tubes of said lower frame has a hollow stop plug defining a central hole connected to an upper end of said lower tube for said middle tube to extend therethrough; each of said left and said right upper tubes of said upper frame has a locating piece connected to a lower end of said upper tube, said locating piece including a radial hole for accommodating a tension spring and a steel ball therein, said steel ball being normally pushed outward by said tension spring; each of said middle tubes has a hollow stop plug defining a central hole connected to an upper end of said middle tube for said upper tube to extend therethrough, and a locating piece connected to a lower end of said middle tube; said locating piece including a radial hole for accommodating a tension spring and a steel ball therein, said steel ball being normally pushed outward by said tension spring; each of said lower tubes of said lower frame is provided near the upper end with a locating hole adapted to engage with said steel ball in said locating piece connected to the lower end of said middle tube and thereby automatically locks said middle tube in place when said middle tube is pulled to a fully extended position relative to said lower tube; and each of said middle tubes is provided near the upper end with a locating hole adapted to engage with said steel ball in said locating piece connected to the lower end of said upper tube and thereby locks said upper tube in place when said upper tube is pulled to a fully extended position relative to said middle tube.
 2. The telescopic handle for luggage cart as claimed in claim 1, wherein each of said hollow stop plugs connected to the upper end of said middle tube has an inner diameter smaller than an outer diameter of said locating piece connected to the lower end of said upper tube, and each of said hollow stop plugs connected to the upper end of said lower tube has an inner diameter smaller than an outer diameter of said locating piece connected to the lower end of said middle tube.
 3. The telescopic handle for luggage cart as claimed in claim 1, wherein each of said locating pieces connected to the lower end of said upper tube has an outer diameter similar to an inner diameter of said middle tube, and each of said locating pieces connected to the lower end of said middle tube has an outer diameter similar to an inner diameter of said lower tube.
 4. A telescopic handle for luggage cart, comprising a lower frame for firmly connected to a trunk or a luggage seat of a luggage cart, and an upper frame, said lower frame including left and right square lower tubes, and said upper frame including left and right square upper tubes and a handle grip connected to upper ends of said left and said right upper tubes; said telescopic handle being characterized in that: each of said left and said right lower tubes of said lower frame has a hollow stop plug defining a central hole connected to an upper end of said lower tube for said upper tube to extend therethrough; each of said left and said right upper tubes of said upper frame has a locating piece connected to a lower end of said upper tube, said locating piece including a radial hole for accommodating a tension spring and a steel ball therein, said steel ball being normally pushed outward by said tension spring; and each of said lower tubes of said lower frame is provided near the upper end with a locating hole adapted to engage with said steel ball in said locating piece connected to the lower end of said upper tube and thereby automatically locks said upper tube in place when said upper tube is pulled to a fully extended position relative to said lower tube.
 5. The telescopic handle for luggage cart as claimed in claim 4, wherein each of said hollow stop plugs connected to the upper end of said lower tube has an inner diameter smaller than an outer diameter of said locating piece connected to the lower end of said upper tube.
 6. The telescopic handle for luggage cart as claimed in claim 4, wherein each of said locating pieces connected to the lower end of said upper tube has an outer diameter similar to an inner diameter of said lower tube. 